The invention relates to gas panels and more particularly to such devices where information stored and displayed therein may be shifted horizontally or vertically in a single row or multi-row display.
Gas panels using conventional X-Y matrix addressing are expensive to implement, since they conventionally require individual drivers for each horizontal and for each vertical line. Using an 80 character single row display with 7.times.9 character dot matrix, addressing would require 560 vertical drivers, to activate selected vertical conductors to ionize the gas at selected coordinate intersections. One alternative to X-Y matrix addressed panels known in the art is the shift gas panel, one example of which is shown in U.S. Pat. No. 3,795,908 "Gas Panel with Multi-Directional Shifting Arrangement" issued to Allen W. McDowell and Frank M. Lay and assigned to the assignee of the instant invention. Such shift systems employ a three or more phase sequential drive arrangement whereby only three or more vertical drivers are required for the entire panel. Data is entered on one end of the panel and sequentially shifted in any direction until the entire message is displayed. While providing substantial cost savings in drive circuitry, such panels are generally limited in character capacity, since the entire display must be updated at a high repetition rate to prevent dimming. The term dimming refers to a visual distraction presented during character entry or update by characters entering the display at a speed slow enough to be noted but not followed by the eye. Typically such speed could be 70 inches per second. Thus heretofore in the art, shift gas panels have been generally relegated to the low end high aspect ratio displays. There is a need therefore to increase the speed and eliminate the phenomenon of the shift gas panel, and it is toward a solution of these problems that the present invention is directed.